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Abstract:

A dew-condensation detecting apparatus includes a dew-condensation
detector provided in a middle of a cold-liquid supply passage. The
cold-liquid supply passage supplies a cooling liquid to electronic
equipment. The dew-condensation detector detects dew condensation by
detecting water droplets due to the dew condensation. A heating part
heats the cooling liquid which has exited from the dew-condensation
detector.

Claims:

1. A dew-condensation detecting apparatus comprising: a dew-condensation
detector provided on a cold-liquid supply passage, which supplies a
cooling liquid, to detect dew condensation by detecting water droplets
due to the dew condensation; and a heating part that heats the cooling
liquid which has exited from said dew-condensation detector.

2. The dew-condensation detecting apparatus as claimed in claim 1,
wherein said heating part includes an electric heater.

3. The dew-condensation detecting apparatus as claimed in claim 1,
wherein said heating part includes an exhaust cooling apparatus.

4. The dew-condensation detecting apparatus as claimed in claim 1,
wherein said heating part includes a heat transfer member and a heat
generator provided to the heat transfer member.

5. An electronic equipment cooling system comprising: a liquid-cooled
electronic equipment of which internal parts are cooled by a cooling
liquid; a cooling-liquid supply apparatus producing the cooling liquid
supplied to said liquid-cooled electronic equipment; a supply passage
connecting said cooling-liquid supply apparatus and said liquid-cooled
electronic equipment to supply the cooling liquid from said
cooling-liquid supply apparatus to said liquid-cooled electronic
equipment; a return passage connecting said liquid-cooled electronic
equipment and said cooling-liquid supply apparatus to return the cooling
liquid from said liquid-cooled electronic equipment to said
cooling-liquid supply apparatus; a dew-condensation detector provided on
said supply passage; and a heating part provided between said
dew-condensation detector and said liquid-cooled electronic equipment to
heat the cooling liquid entering said liquid-cooled electronic equipment.

6. The electronic equipment cooling system as claimed in claim 5, wherein
said heating part includes an electric heater provided to said supply
passage.

7. The electronic equipment cooling system as claimed in claim 5, wherein
said heating part includes an exhaust cooling apparatus that cools an
exhaust of said liquid-cooled electronic equipment.

8. The electronic equipment cooling system as claimed in claim 5, wherein
said heating part includes a heat transfer member provided to said supply
passage and a heat generator provided to the heat transfer member.

9. The electronic equipment cooling system as claimed in claim 8, wherein
said heat generator includes peripheral equipments or peripheral parts of
said liquid-cooled electronic equipment.

10. A dew-condensation detecting method comprising: heating cooling
liquid after exiting a dew-condensation detector and before entering an
electronic equipment; detecting dew-condensation by said dew-condensation
detector and supplying a dew-condensation detection signal to said
electronic equipment.

11. The dew-condensation detecting method as claimed in claim 10, further
comprising turning off a power of said electronic equipment based on said
dew-condensation detection signal.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based upon and claims the benefit of priority
of the prior Japanese Patent Application No. 2011-038920, filed on Feb.
24, 2011, the entire contents of which are incorporated herein by
reference.

FIELD

[0002] The embodiment discussed herein is directed to a dew-condensation
detecting apparatus for detecting dew-condensation by detecting water
droplets generated by dew condensation.

BACKGROUND

[0003] When a temperature of a component of electronic equipment goes down
to a temperature below a dew point of circumambient air, dew condensation
occurs on a surface of the component of the electronic equipment. A water
component generated by the dew condensation may cause corrosion of metal
parts of the electronic equipment or cause short-circuiting between
electrodes of an electric circuit inside the electronic equipment, which
may cause a problem due to dew condensation.

[0004] Generally, temperature and humidity of an environment of
liquid-cooled electronic equipments are managed so that dew condensation
does not occur. However, if an air conditioner malfunctions or a
temperature abnormality occurs in a cooling liquid output apparatus, a
temperature of a cooling liquid, which reaches the electronic equipment,
may be below a dew point, and, thereby, the interior of the electronic
equipment may be set in a dew-condensation condition. It is possible that
a power of the electronic equipment is turned on, or the electronic
equipment continues to operate in such a dew-condensation condition. In
such a case, if an amount of water droplets due to dew condensation
exceeds a certain amount in the interior of the electronic equipment,
short-circuiting between electrodes may occur in an electric circuit in
the interior of the electronic equipment, which may cause an erroneous
operation or burn-out of the electric circuit.

[0005] In order to prevent such a problem due to dew condensation, it is
suggested to detect dew condensation by providing a dew-condensation
sensor in an electronic equipment to take measures for dew condensation.
That is, if dew condensation is detected by the dew-condensation sensor,
the electronic equipment is prohibited from being turned on, or a
dehydrating process is performed inside the electronic equipment.

[0006] There are some kinds of dew-condensation sensors. A
due-condensation water detecting sensor is known which detects dew
condensation by detecting water droplets, which are generated due to dew
condensation, flowing and reaching a detecting part. Such a
dew-condensation sensor generally includes a measuring object formed by a
metal, which tends to generate dew condensation, and a water-droplet
sensor (a liquid sensor) to detect water droplets formed on the measuring
object. The measuring object is provided in a cold-water supply passage
between a cold-water supply apparatus and electronic equipment so that
the measuring object is cooled by cold water supplied from the cold-water
supply apparatus. Accordingly, if the temperature of the measuring object
becomes below a dew point of an atmosphere, dew condensation occurs on
the measuring object. That is, the cold water supplied from the
cold-water supply apparatus cools the measuring object of the
dew-condensation water detecting sensor, and, thereafter, the cold water
is supplied to the electronic equipment and cools a heat-generating part
inside the electronic equipment.

[0007] The heat capacity of the measuring object of the dew-condensation
detecting sensor is small, and is not a heat-generating object. Thus, a
temperature of the cold water entering the electronic equipment after
cooling the measuring object hardly changes from a temperature of the
cold water supplied from the cold water supply apparatus to the measuring
object. Therefore, if dew condensation occurs on the measuring object, it
is possible that dew condensation occurs also on the cold water passages
inside the electronic equipment at almost the same time.

[0008] There is suggested a cooling apparatus, which, if dew condensation
occurs on a heat exchanger, warms near an outlet of the heat exchanger to
eliminate the dew condensation (for example, refer to Japanese Laid-Open
Patent Application No. 10-9735). The cooling apparatus can eliminate dew
condensation near the outlet of the heat exchanger but may not eliminate
dew condensation inside the electronic equipment. Additionally, the
cooling apparatus eliminates dew condensation by warming-up by a heater
only after detecting dew condensation which has already occurred.

[0009] Because the dew-condensation water detecting sensor detects dew
condensation by detecting water droplets generated by dew condensation as
mentioned above, a certain time period must be passed from a time of
initiation of dew condensation until an amount of water droplets
generated by dew condensation reaches a detectable amount. It is possible
that water droplets are generated due to dew condensation in the
electronic equipment during the time period from a time of initiation of
dew condensation in the dew-condensation water detecting sensor and
inside the electronic equipment until the dew-condensation water
detection sensor detects the dew condensation. The water droplets caused
by the dew condensation may cause the above-mentioned problem in the
electronic equipment.

SUMMARY

[0010] There is provided according to an aspect of the invention a
dew-condensation detecting apparatus including: a dew-condensation
detector provided in a middle of a cold-liquid supply passage, which
supplies a cooling liquid, to detect dew condensation by detecting water
droplets due to the dew condensation; and a heating part that heats the
cooling liquid which has exited from the dew-condensation detector.

[0011] There is provide according to another aspect an electronic
equipment cooling system including: a liquid-cooled electronic equipment
of which internal parts are cooled by a cooling liquid; a cooling-liquid
supply apparatus producing the cooling liquid supplied to the
liquid-cooled electronic equipment; a supply passage connecting the
cooling-liquid supply apparatus and the liquid-cooled electronic
equipment to supply the cooling liquid from the cooling-liquid supply
apparatus to the liquid-cooled electronic equipment; a return passage
connecting the liquid-cooled electronic equipment and the cooling-liquid
supply apparatus to return the cooling liquid from the liquid-cooled
electronic equipment to the cooling-liquid supply apparatus; a
dew-condensation detector provided in a middle of the supply passage; and
a heating part provided between the dew-condensation detector and the
liquid-cooled electronic equipment to heat the cooling liquid entering
the liquid-cooled electronic equipment.

[0012] There is provided according to a further aspect a dew-condensation
detecting method including heating cooling liquid after exiting a
dew-condensation detector and before entering an electronic equipment;
detecting dew-condensation by the dew-condensation detector and supplying
a dew-condensation detection signal to the electronic equipment.

[0013] The object and advantages of the embodiment will be realized and
attained by means of the elements and combinations particularly pointed
out in the appended claims.

[0014] It is to be understood that both the foregoing general description
and the following detailed description are exemplary explanatory only and
are not restrictive of the invention, as claimed.

BRIEF DESCRIPTION OF DRAWINGS

[0015]FIG. 1 is an outline diagram illustrating an entire electronic
equipment cooling system including a dew-condensation detecting apparatus
according to a first embodiment;

[0017]FIG. 3 is an outline diagram illustrating an entire electronic
equipment cooling system including a dew-condensation detecting apparatus
according to a second embodiment;

[0018]FIG. 4 is a perspective view of electronic equipment attached with
an exhaust cooling apparatus; and

[0019]FIG. 5 is an outline diagram illustrating an entire electronic
equipment cooling system including a dew-condensation detecting apparatus
according to a third embodiment.

DESCRIPTION OF EMBODIMENT(S)

[0020] Embodiments of the present invention will be explained with
reference to the accompanying drawings.

[0021]FIG. 1 is an outline diagram illustrating an entire electronic
equipment cooling system including a dew-condensation detecting apparatus
according to a first embodiment.

[0022] In FIG. 1, electronic equipment 10 is, for example, a liquid-cooled
electronic equipment such as, for example, a computer or a server.
Heat-generating parts (for example, a semiconductor device or a power
supply circuit) inside the electronic equipment 10 are cooled by cooling
water, which is an example of cooling-liquid, of a low temperature
(hereinafter, referred to as cold water) supplied by a cold-water supply
apparatus 12. The cold water produced by the cold-water supply apparatus
12 is supplied to a cooling water passage (not illustrated in the figure)
in the electronic equipment through a cold-water supply pipe passage 14.
The heat generating parts are arranged in the middle of the cooling water
passage. The cold water flowing through the cooling water passage absorbs
heat from the heat-generating parts to cool the heat-generating parts.
The cooling water warmed by cooling the heat-generating parts
(hereinafter, referred to as warm water) is returned from the cooling
water passage inside the electronic equipment 10 to the cold-water supply
apparatus 12 through the warm-water return pipe passage 16.

[0023] Although the cold-water supply apparatus 12 is a known
cooling-water cooling apparatus having, for example, a refrigerator and a
heat exchanger, a cooling-water cooling apparatus having any structure
may be used if it is an apparatus capable of producing cold water by
cooling warm water discharged from the electronic equipment 10 and
supplying the warm water to the electronic equipment 10. Generally, a
plurality of electronic equipments 10 are provided to one cold-water
supply apparatus 12.

[0024] A dew-condensation sensor 20, which is an example of a
dew-condensation detector, is provided in the middle of the cold-water
supply pipe passage 14 provided between the cold-water supply apparatus
12 and the electronic equipment 10. If the cold-water supply pipe passage
14 is short, the dew-condensation sensor 20 may be provided at an
arbitrary position along the cold-water supply pipe passage 14. If the
cold-water supply pipe passage 14 is long, it is desirable to arrange the
dew-condensation sensor 20 at a position close to the electronic
equipment 10. This is because, if an environment (temperature and
humidity) around the dew-condensation sensor 20 is equivalent to an
environment (temperature and humidity) inside or around the electronic
equipment 10, it can be regarded that dew-condensation detection
performed by the dew-condensation sensor 20 is equivalent to
dew-detection performed inside the electronic equipment 10.

[0025] The dew-condensation sensor 20 detects water droplets generated by
dew condensation on the measuring object, and outputs a dew-condensation
detection signal. The dew-condensation detection signal output by the
dew-condensation sensor 20 is supplied to a service processor 10b
provided in a control part 10a of the electronic equipment 10. The
service processor 10b is a CPU, which performs a control to cause some
functions of the electronic equipment 10 to be performed even when a main
power of the electronic equipment 10 is turned off and a main function is
deactivated. For example, if a dew-condensation detection signal is
supplied, the service processor 10b can turn off the main power supply of
the electronic equipment 10 to stop an operation of the electronic
equipment 10.

[0026] A heater 30, which is an example of a heating part, is provided
between the dew-condensation sensor 20 and the electronic equipment 10.
The heater 30 is provided to raise the temperature of cold-water entering
the electronic equipment 10 by heating the cold water, which has passed
through the dew-condensation sensor 20. For example, if a temperature of
cold water passing through the dew-condensation sensor 20 is 21°
C., the cold water of 21° C. is heated by the heater 30 at, for
example, 23° C. so that the cold-water of 23° C. enters the
electronic equipment 10.

[0027] For example, it is assumed that an environment in a server room
where the electronic equipment 10 is installed is maintained with a room
temperature of 25° C. and a relative humidity of 50% or less, and
the temperature of the cold-water supplied from the cold-water supply
apparatus 12 is 21° C. In such an environment in the server room,
it can be found by acquiring from the psychrometric chart that the dew
point temperature at the dew-point sensor 20 and inside the electronic
equipment 10 is 13.9° C. Accordingly, in this environment, there
is no dew-condensation occurs because the temperature is below the
dew-point temperature (13.9° C.) at the dew-condensation sensor 20
(of which temperature is 21° C., which is the same as the cold
water) and also at the cooling water passage (of which temperature is
23° C., which is the same as the cold water heated by the heater
30) inside the electronic equipment 10.

[0028] Here, it is assumed that the environment in the server room has
changed due to, for example, a failure in an air-conditioning machine,
and the room temperature is raised to 28° C. and the relative
humidity is raised to 70%. At this time, the dew-condensation temperature
in the environment in the server room is raised to 22° C., which
is higher than the temperature 21° C. of the cold water.
Accordingly, dew-condensation occurs at the dew-condensation sensor 20 of
which temperature is 21° C., which is the same as the cold water.
On the other hand, the cooling water passage in the electronic equipment
10 is at 23° C., which is the same temperature as the cold water
heated by the heater 30.

[0029] If the environment in the server room continues to change and the
room temperature or the relative humidity raises, the dew point
temperature rises further from 22° C. Then, if the dew point
temperature exceeds the temperature of 23° C. of the cold water
heated by the heater 30, dew condensation occurs also inside the
electronic equipment 10.

[0030] However, it takes a certain time from a time at which the dew point
temperature reaches at 21° C. of the dew-condensation sensor 20
until a time at which the dew point temperature reaches at 23° C.
of the cooling water passage in the electronic equipment 10. During that
time period, the dew-condensation at the dew-condensation sensor 20
progresses and the droplets are grown, which results in an amount of
droplets becoming detectable by the dew-condensation sensor 20. That is,
no dew-condensation is initiated in the electronic equipment 10 and,
thus, no water droplets are produced during the time period from a time
at which dew condensation is initiated at the dew-condensation sensor 20
due to a change in the environment in the server room until a time at
which the dew-condensation sensor 20 outputs the dew-condensation
detection signal.

[0031] Therefore, a problem in the electronic equipment 10 due to
dew-condensation can be prevented from occurring by taking measures such
as turning a power of the electronic equipment 10 off upon reception of
the dew-condensation detection signal output from the dew-condensation
sensor 20.

[0032] A description will now be given, with reference to FIG. 2, of a
dew-condensation detecting method performed in the electronic equipment
cooling system. FIG. 2 is a flowchart of a dew-condensation detecting
process.

[0033] When the dew-condensation detecting process is started, first, the
heater 30 is turned ON to perform heating of the cold water by the heater
30 (step S1). The time of turning ON the heater 30 may be a time of
turning ON a power of the electronic equipment 10 or a time of starting
supply of cold water to the electronic equipment 10. When supplying cold
water to the electronic equipment 10, it is desirable to always turn ON
the heater 30.

[0034] Then, the service processor 10b of the control part 10a of the
electronic equipment 10 acquires a signal from the dew-condensation
sensor 20 when the electronic equipment 10 is in operation and
heat-generating parts inside the electronic equipment 10 are being cooled
(step S2). Subsequently, the service processor 10b of the electronic
equipment 10 determines whether the signal from the dew-condensation
sensor 20 is a dew-condensation detection signal which indicates that dew
condensation is detected (step S3). If it is determined in step S3 that
the signal from the dew-condensation sensor 20 is not the
dew-condensation detection signal, the process returns to step S2 and the
service processor 10b acquires a signal from the dew-condensation sensor
20 again.

[0035] On the other hand, if it is determined in step S3 that the signal
from the dew-condensation sensor 20 is the dew-condensation detection
signal, the process proceeds to step S4. In step S4, the service
processor 10b performs a process of interrupting (turning OFF) the power
of the electronic equipment 10. At this time, a notification of the fact
that a dew-condensation condition is established may be sent to a manager
by using a display device or issuing a warning. Or, instead of turning
OFF the power of the electronic equipment 10, a process of dehydrating
the interior of the electronic equipment 10 may be performed to eliminate
the dew condensation.

[0036] While the above-mentioned dew-condensation detecting process is
performed, the cold water after passing through the dew-condensation
sensor 20 and before entering the electronic equipment 10 is heated by
the heater 30 so that the cold water is set to a temperature higher than
the temperature at the dew-condensation sensor 20. Accordingly, during
the time after the initiation of the dew condensation at the
dew-condensation sensor 20 until the dew condensation is detected by the
dew-condensation sensor 20, no dew condensation occurs inside the
electronic equipment 10. Thus, measures for dew-condensation can be taken
such that, for example, the power of he electronic equipment 10 is turned
OFF, thereby preventing a problem due to dew condensation inside the
electronic equipment 10.

[0037] Although the dew-condensation sensor 20 and the heater 30 are
arranged outside and near the electronic equipment 10 in FIG. 2, if a
sufficient space can be reserved inside the electronic equipment 10, the
dew-condensation sensor 20 and the heater 30 may be provided inside the
electronic equipment 10.

[0038] Moreover, although the heater 30 is attached to the
dew-condensation sensor 20 in FIG. 2, it is desirable to provide a heat
insulator between the heater 30 and the dew-condensation sensor 20 so
that the heat of the heater 30 is not transmitted to the dew-condensation
sensor 20. Alternatively, the heater 30 may be arranged at a position
remote from the dew-condensation sensor 20. The heater 30 may be arranged
at an arbitrary position if it can raise the temperature of the cold
water after exiting from the dew-condensation sensor 20 and before
entering the electronic equipment 10. The dew-condensation sensor 20 and
the heater 30 together constitute the dew-condensation detecting
apparatus.

[0039] As for the heater 30, a heater performing heating by electric
energy, such as an electric heater (resistance heating heater) or an
induction heater, may be used. Instead of using the heater 30, the cold
water may be heated by exhaust heat from the electronic equipment 10.
Moreover, instead of using the heater 30, the cold water may be heated
using heat from heat-generating parts of peripheral equipments of the
electronic equipment 10.

[0040] A description will be given below of a second embodiment. FIG. 3 is
an outline diagram of an entire electronic equipment cooling system
including a dew-condensation detecting apparatus according to the second
embodiment. In FIG. 3, parts that are the same as the parts illustrated
in FIG. 1 are given the same reference numerals, and descriptions thereof
will be omitted.

[0041] In the electronic equipment cooling system illustrated in FIG. 3,
an exhaust cooling apparatus 40 is used as a heating part for heating
cold water. That is, instead of heating cold water by the heater 30, the
exhaust cooling apparatus 40 is used to heat the cold water. FIG. 4 is a
perspective view of the electronic equipment 10 attached with the exhaust
cooling apparatus 40.

[0042] In many cases, the electronic equipment 10 is provided with an
air-cooling mechanism besides a mechanism to cool the heat-generating
parts inside the electronic equipment 10 as mentioned above. The
air-cooling mechanism cools the internal parts of the electronic
equipment 10 using air taken into the electronic equipment 10. As for the
air-cooling mechanism, an air blower such as a fan may be used to take
air outside the electronic equipment 10 and ventilate the interior of the
electronic equipment 10. The warmed air after cooling the interior of the
electronic equipment 10 is exhaust outside the electronic equipment 10.

[0043] The exhaust cooling apparatus 40 is a heat exchanger for cooling
the air exhausted outside from the electronic equipment 10. For example,
the exhaust cooling apparatus 40 cools air exhausted from the electronic
equipment 10 by causing the air exhausted from the electronic equipment
10 to pass therethrough while flowing cooling water supplied from an
external part. In the present embodiment, the cold water passed through
the dew-condensation sensor 20 is used as the cooling water to be
supplied to the exhaust cooling apparatus 40.

[0044] That is, the cold-water supply pipe passage 14 extending from the
dew-condensation sensor 20 is connected to the cooling-water passage of
the exhaust cooling apparatus 40. The cold water, which exited from the
dew-condensation sensor 20, flows through the cooling water passage of
the exhaust cooling apparatus 40 and cools the air exhausted from the
electronic equipment 10, and, thereby, the cold water absorbs heat of the
exhaust air and a temperature thereof is raised. Accordingly, similar to
heating by the heater 30, the cold water can be heated by the exhaust
cooling apparatus 40 and a temperature of the cold water can be raised.

[0045] Although FIG. 4 illustrates, for the purpose of illustration, a
state where the interior of the electronic equipment 10 is exposed by
removing the exhaust cooling apparatus 40 from the electronic equipment
10, the exhaust cooling apparatus 40 actually covers the exhaust surface
of the electronic equipment 10.

[0046] According to the present embodiment, an effect of energy saving can
also be obtained because the cold water is heated by using exhaust heat
from the electronic equipment 10.

[0047] A description will be given below of a third embodiment. FIG. 5 is
an outline diagram of an entire electronic equipment cooling system
including a dew-condensation detecting apparatus according to the third
embodiment. In FIG. 5, parts that are the same as the parts illustrated
in FIG. 1 are given the same reference numerals, and descriptions thereof
will be omitted.

[0048] In the electronic equipment cooling system illustrated in FIG. 5, a
heat transfer member 50 is used as a heating part for heating the cold
water. That is, instead of the heater 30 to heat the cold water, the heat
transfer member 50 to which a heat generator 52 is attached is used to
heat the cold water.

[0049] The heat transfer member 50 is formed of a material such as, for
example, a metal plate having a large thermal conductivity.
Alternatively, a heat pipe may be use as the heat transfer member 50. The
heat transfer member 50 is attached with the heat generator 52 as a heat
source. By using a heat generating part such as peripheral equipments or
peripheral parts of the electronic equipment 10 as the heat generator 52,
an effect of exhaust heat recovery can be obtained. However, for example,
an exclusive heater may be used as the heat generator 52

[0050] All examples and conditional language recited herein are intended
for pedagogical purposes to aid the reader in understanding the
principles of the invention and the concepts contributed by the inventor
to furthering the art, and are to be construed a being without limitation
to such specifically recited examples and conditions, nor does the
organization of such examples in the specification relates to a showing
of the superiority and inferiority of the invention. Although the
embodiment(s) of the present invention(s) has(have) been described in
detail, it should be understood that the various changes, substitutions,
and alterations could be made hereto without departing from the spirit
and scope of the invention.